Coupler
Couplers, also known as Couplings are mechanical assemblies that join railcars so to makeup a trains consist. The couplers, track gage, brakes, clearances, etc of a given railcar, are just some of many factors that determine compatibility with other pieces of rollingstock & a specific railway. An entire Coupler assembly typically includes various components; knuckle, head, shank, release, striker, yoke, follower, drawgear... RailCar couplers are very generally categorized as follows: * FullManual Couplers require a trainman to step between cars to manually couple+decouple mech +pneu +elec connections. * SemiAuto Couplers automaticly couple+decouple the mech connection, but require manual pneu +elec connections. * FullAuto Couplers automaticly couple+decouple all mech +pneu +elec connections. Link&Pin Couplers This coupler is a FullManual design that originated on NAmerican railways in the early 1800s. Link&Pin couplers are cheap to make, functionally simple, yet very dangerous to use: a drawbar\buffer projecting away from the railcar frame allows access to a vertical pin that holds a link in place; the link extends out the end of the drawbar\buffer; as cars come together, the opposite pin is raised by one hand of the trainman while his other hand guides the link into the opposing drawbar\buffer, then the pin is lowered thru the common link, thus coupling the cars. Uncoupling is the reverse procedure & only slightly less dangerous for the trainman. As North American railways expanded & became more interconnected, Link&Pin couplers became more problematic: injury & death to trainmen due to these couplers became common as RailCars became heavier; loose Pins & Links often were missing or the wrong size. Finally in 1893 the US Congress mandated a 10+Year transition, outlawing the Link&Pin, along with other lesser coupler types of that era, & required newly developed Janney couplers (per MasterCarBuilder\MCB standards) for NAmerican 4f708 1m435 Gage interchange. In the years since, Link&Pin couplers have been generally outlawed worldwide, now only seen on Preserved\Museum stock & isolated Colonial\Industry\Mine\Plantation stock. 3Link Couplers This coupler is a FullManual design that originated on British railways in the early 1800s, & yet just recently have been removed from service with the retirement of legacy BritishRailways\BR LooseCoupled Goods\Freight stock. The 3Link Coupler is cheap to make & simple yet dangerous to use. Stock fitted with this coupler have a drawhook connecting to internal draftgear, along with a pair of sprung buffers on each end of the car. A 3Link chain hangs from a gedge\notch in each hook shank; after 2 cars are pushed together, one of the two 3Link chains is lifted into the opposing hook. A shunting pole can be used to manipulate the chains, which is somewhat safer than being between the buffers. A disadvantage of this design is the resulting "loose" coupling, meaning several inches of slack is inherent, which must be taken up in tension as the consist accelerates & again compressed as the consist decelerates. This causes much wear & tear on each cars structure, draftgear, buffers & lading, thus as improved coupler designs became available, only slow goods\freight stock were allowed to use 3Link Couplers. An advantage is less of the consists weight is on the locomotive as it accelerates, thus why this coupler remained is use so long. The legacy BR 3Link Coupler is compatible with legacy BR Instanter Couplers & standard BR\EU\UIC Screw Couplers. Instanter Couplers This coupler is a FullManual design. AlsoKnownAs Close Couplers, this coupler is a mechanical improvement over 3Link Couplers; the center link is now replaced with a special triangular link, allowing 2 positions: LooseCoupled for shunting or CloseCoupled for mainline running. A shunting pole may be used to connect\disconnect\adjust the links. Screw Couplers This coupler is a FullManual design, & has become standard on British +Irish +European rollingstock, both in Goods\Freight & Passenger service. Screw Couplers are a mechanical improvement over 3Link & Instanter Couplers; in essence this is a 3Link with an OpposingThread TurnBuckle replacing the center link. However this design is more dangerous: shunting poles can not be used, thus trainmen must go between cars+buffers to connect\disconnect this coupler. Standard BR\EU\UIC Screw Couplers are generally compatible with legacy BritishRailways 3Link +Instanter couplers. Janney\AAR Couplers Janney\AAR couplers, AlsoKnownAs APT\ARA\MCB couplers, are a SemiAuto design; meaning mechanical mating +separation is automatic; any required PneumaticPipe+ElectricCable connection is seperate & manual. Inspired by the human hand, then patented 1873~1914 by E.Janney Of USVI, the design was steadily improved thru several decades by the McConway&TorleyCo, PennsylvaniaRailRoad\PRR, MasterCarBuilders\MCB, AmericanRailwayAssoc\ARA, AmericanAssocRailways\AAR & AmericanPublicTransportion\APT to become a practical reliable coupler, requiring little maintenance, durable in abusive service & extreme environments. : : AAR couplers operate much like Willison couplers, but with jointed\hinged nucks instead of interlocking heads. At least one nuck must be open to allow mating; as 2 cars come together, the nucks are pushed closed by the palm of the opposing coupler until latch pins hold the nucks locked. To decouple, cars are pushed together for slack, one pin is raised with a side lever allowing that nuck to open & the cars are free to part. An advantage over Willison couplers is AAR couplers intentionally have Nucks of lower strength than the Head or Shank, thus the Nuck acts as a ShearPin when overstressed & is readily replaced onsite by the train crew; a disadvantage is Willison couplers mate without concern for Nuck closed\open position. : : AARC\MCB5\Transition couplers were mandated by the US Congress in 1893, which forced replacing dangerous Link&Pin couplers on Freight stock & unreliable MillerHookPlatform couplers on Passenger stock, greatly reduced injuries & allowed efficient interchange of rollingstock amongst 4f708 1m435 StandardGage railroads across NAmerica. AARC\MCB5\Transition couplers have Contour#5, 9i25 LongHeads (MateLine~Horn) & 9i TallNucks; upto 21i TallNucks were used on Tram+Logging+Ferry stock to allow running on rough\uneven track. They mate to all other AAR\APT\ARA\MCB standard subtypes & connect to the outlawed Link&Pin+MillerHookPlatform couplers when fitted with a SplitNuck. : : AARC\MCB5\Sharon couplers (make.model=NaCo.Sharon) are typical of AARC\MCB5 designs & many remain in use on legacy\museum stock as of this 2019 writing. : : AARC\UICD\DropHead couplers (make.model=BECo.DropHead) were first designed ~1898 by N.Gresley of Britain & manufactured by BuckEyeCo of USOh specificly for PassengerCorridor stock & have since been produced at UK\EU foundries & used on British +Irish PassengerMultiUnit +FreightUnit stock. AARC\UICD\DropHead couplers have Contour#5, 9i25 LongHeads, 9i TallNucks & mate to all other AAR\APT\ARA\MCB standard subtypes. They pivot downward to reveal a BR\EU|UICD coupler hook for use in emergencies. : : AARD\ASF3\Alliance couplers (make.model=ASF.Model3\Alliance) were first designed ~1913 by R.Janney (son of E.Janney) & manufactured by AmericanSteelFoundries at USOh Alliance, in heated competition for the pending 1915 ARAD standard, but lost out to A.Bazeley+NaCo. R.Janney+ASF then defiantly marketed their Alliance design outside of NAmerica as a LessCostly LiteDuty coupler. The Alliance has improved Contour#10, though shorter\weaker 10i LongHeads compared to AAR\ARA standard 12i LongHeads, but remain compatible & mate to all other AAR\APT\ARA\MCB standard subtypes. As various steel foundries around the world (LAFHenricot, OMBES, Sable, TedRail, WCR, BradKen, RIS...) licensed +marketed +improved the design, AARD\ASF3\Alliance couplers & several resulting evolutions became common on Passenger +Freight stock of Australia +Brazil +Britain +Burma +China +Cuba +Dijaboti +Ecuador +Ethiopia +India +Indonesia +Japan +Korea +Malaysia +NewZ +Panama +Phillipines +Saudi +SAfrica +Taiwan +Tanzania +Thai +Vietnam +Zambia +Zimbabwe... : : AARD\ARAD\Bazeley couplers, superceding AARC, became the AARD\ARAD standard in 1915 for both Freight & Passenger duty. AARD couplers have improved Contour#10 & stronger 12i LongHeads + 9i TallNucks; optional 11i TallNucks were often used on Lokomotives. They mate to all other AAR\APT\ARA\MCB standard subtypes. : : AARE\ARAE\GeneralDuty couplers, superceding AARD +AARC, became the AARE standard in 1932 for Routine Freight: BoxCars +CenterBeams +Hoppers +Flats +Gondolas +InterModals +AutoRacks +Reefers... AARE couplers have improved Contour#10A, 12i LongHeads & stronger 11i TallNucks. They mate to all other AAR\APT\ARA\MCB standard subtypes, & are the most common of AAR\APT\ARA\MCB couplers. : : AARF\APTF\InterLock couplers, conceived in 1901 by E.Ramsay@PrattCoalCo of USAL, became the AARF standard in 1954 for HazmatTank+RotaryGondola Freight Wagons & later the APTF standard for DualService=Freight+Passenger Lokomotives. AARF\APTF\InterLock couplers have Contour#10A with SlackPadding, 12i LongHeads & 11i TallNucks. They mate to all other AAR\APT\ARA\MCB standard subtypes, prevent decoupling\punctures in derailments, minimize slack, & allow RotaryDumping of Gondola Freight Wagons. : : AARH\APTH\TightLock couplers evolved from the 1908 VanDorn#20 on the Hudson&Manhattan, the 1909 VanDorn#31 on the Chicago&Southern & the 1915~1927 HType by E.Henricot of Etienne Belgiumused on NMBS\SNCB stock, which were efforts to improve upon MCB5+ARAD+Alliance couplers of that era. A further improved & noticably evolved design, first used 1928 in NAmerica on the NewYorkCentralRR, became the AARH\APTH standard in 1947 for Passenger Lokomotives+Wagons+MultiUnits. AARH couplers have Contour#10A with SlackPadding, 12i LongHeads & 11i TallNucks. They mate to all other AAR\APT\ARA\MCB standard subtypes, prevent decoupling\telescoping in derailments, minimize slack, & allow Pneumatic+Electric appliances that convert AARH couplers from SemiAuto to FullAuto operation. : AARx\SwingHead\DropHead couplers, which pivot to a standard BR\EU\UIC Screw coupler hook, are used on Passenger +Freight\Goods unit trains of Britain +IreLand +SriLanka. : AARx\SwingLink\CentreBuffer couplers, with pivoting standard BR\EU\UIC Screw coupler links, are used on Passenger +Freight\Goods unit trains of India +SriLanka. : Willison Couplers Willisons are SemiAuto couplers originating in 1913 designs by J.Willison@NationalCastingsCo\NaCo of USOh. First intended for abusive duty in extreme environments, the rugid Willison coupler has become a world standard for Farm\Plantation +Mine\Industrial +Colonial\NarrowGage railways, & are available in 050% +075% +Full sizes. Willison Couplers operate much like Janney Couplers, though with interlocking Heads instead of hinged Nucks. A Willison advantage compared to Janneys, is they mate without concern for Nuck closed\open position; a disadvantage is Willisons do not have breakaway Nucks & a broken Head\Shank is not easily repaired by TrainMen. After the original design was enlarged\improved by NaCo Of USOh & LAF Of France, combination Willison+Screw Couplers were used on 1932~1970 French\SNCF.141TC lokomotives & associated passenger cars serving Paris~Nord routes. After further testing\improvement, in 1935 Russia made the Willison\CA3 coupler standard for the entire RZD broadgage railway; this version has cast letters CA3 meaning CоветскихAвто3 in Russian or SA3 meaning SovietAuto3 in English, & is used across continental Russia +FinLand +Mongolia +Ukraine +Turkey +Iran... A newer CоветскихAвтоKuppling5\CAK5\CAKv version is used in Russ~Euro interchange, being compatible with both Russian\RZD CA3 & BR\EU\UIC Screw couplers. Scharfenberg Couplers Scharfenbergs are FullAuto couplers originating in 1903 designs by K.Scharfenberg of Konigsberg Germany. AlsoKnownAs SchaKu\Dellner\Voith couplers, Scharfenbergs have become the most common coupler worldwide to be used on unit passenger trains: DMUs +EMUs +Tram\LRVs... As two Scharfenberg couplers come together, brakepipes mate & cocks automaticly open, & rotating covers reveal electric contacts. To uncouple, a remote release is operated from the cab. Evolutions of the Scharfenberg, Shibata & Shinkansen couplers are standard on Japanese +Korean passenger stock. Relative higher cost\complexity, need for covers\heaters in dirty\winter service, & limited draft ratings, cause this coupler to be rarely used on freight\goods stock. Refs * RailCarCouplers At OBTS Wiki * RailCarCouplers At WikiVisually Category:Locomotive Parts Category:Steam Locomotive Principles Category:Diesel Locomotive Principles Category:Electric Train Principles Category:Encyclopedic articles